1. Field of the Invention
This invention relates to an apparatus for truing a grinding wheel. More particularly, it is a truing apparatus including a truing tool mounted on a truing head which is movable relative to a grinding wheel in parallel to the outer peripheral surface thereof and at right angles thereto to move the tool to its truing position.
2. Discription of the Prior Art
A truing tool is employed in a grinding machine for truing a grinding wheel which comprises a metal disk, as of aluminum, having an outer peripheral surface carrying thereon a layer of hard abrasive grains of cubic boron nitride. The thermal expansion or contraction of the grinding wheel, however, causes the position of its outer peripheral surface to change relative to the truing tool. It is, therefore, difficult to ensure the accurate movement of the truing tool by a distance which is required for its proper truing operation.
In this connection, U.S. Pat. No. 4,266,374 to H. Asano et al. shows a truing apparatus including a detection member mounted on a truing head movably toward a grinding wheel so as to be ground by the grinding wheel which has been trued, so that it may be aligned with a truing wheel on the outer periphery of the grinding wheel, and so that the contact of the detection member with the outer peripheral surface of the grinding wheel may be detected to provide a basis for controlling the distance by which the truing wheel is moved for truing the grinding wheel.
This apparatus has, however, the following drawbacks:
(1) It is complicated in construction, since it requires a mechanism for feeding the contact detection member by a certain distance toward the truing head whenever the grinding wheel has been trued; and PA1 (2) As the contact detection member is ground whenever the grinding wheel has been trued, it is worn out rapidly and need be changed to a new one frequently.